Finite Element Simulation of Heat Transfer in Laser Additive Manufacturing of AlSi10Mg Powders

Abstract

Abstract In the digital world, direct metal laser sintering (DMLS) is known as a laser-based additive manufacturing process, which grabs the attention of manufacturing industries to make the components directly from metal powder. It is a high-temperature process in which the metal particles are fused with laser power to form a full dense homogenous structure. The quality of fabricated parts depends on the heat transfer mechanism, temperature distribution, and molten pool formation in the powder bed, which directly influence by the process parameters such as scan speed, laser power, hatch spacing, powder layer thickness, and laser spot diameter. So it is necessary and important to understand the characteristics and mechanism of these thermal processes. The heat transfer mechanism involves conduction, convection, and radiation, which affects the formation of internal stresses that leads to deformation. In response to this fact, it was indispensable to analyze the thermal behavior in the powder bed instantly during the DMLS process and subsequently monitor the process parameters in order to obtain acceptable manufacture outputs intended for further use. The present research work focused to develop a finite element model for the prediction of temperature distribution and molten pool formation during sintering process of AlSi10Mg composite powders using ANSYS 17.0. The temperature distribution, thermal history, molten pool dimension and sintering depth in direct metal laser sintering process were investigatedat different laser spot diameter and powder layer thickness. From the simulation result, it was observed that as the laser spot diameter increases from 2mm to 6mm, the surface temperature of the molten pool decreases 4626°C to 541°C. So that molten pool length, width and sintering depth of powder bed decrease 3mm to 0 mm. Similarly, as powder bed layer thickness increases from 1mm to 3mm, the field temperature of the molten pool decreases 1200°C to 1075°C and the sintering depth decreases 0.243mm to 0.112mm. This model will be an important tool for the development of optimized process controls and cooling strategies